Preparation And Characterization Of Biochar From Water Hyacinth Supported Nanoscale Zero-valent Iron(nZVI) And Its Adsorption Properties Research On Cadmium

Excessive reproductions of water hyacinth and cadmium pollution in water have become two severe problems being confronted nowadays.Rapid propagation of water hyacinth caused a decline in dissolved oxygen concentration,thus inhibiting the growth of other species,causing biodiversity loss and even ecosystem collapse.Cadmium posed a major threaton the environment and human healthwithhigh chemical activity,high mobility and durable toxicity.As an efficient adsorption materials,nano-ironsurpported on porous materials as biochars can not only maintain the efficient adsorption capacity and reduce aggregation,but use the high stability,high mechanical strength ofbiocharsin the removal of heavy metals in water environmentIn this study,the preparation of biochars(BC)fromwater hyacinth supported Nanoscale Zero-valent Iron(n ZVI/BC)was investigated byliquid reduction method.Chemical methods and spectrum technologies as FTIR,XRD and SEM-EDS were used to characterize their composition and structure properties.Besides,the sorption kinetics,isotherms andregeneration performance were also investigated.The main original conclusions of this work are drawn as follows.(1)Results of SEM-EDS,FTIR and XRD analysis that nano-iron particles were successfully loaded on modified biocharss with good dispersion capacity.The surface area ofnZVI/BCincreased by 43.13% and the total pore volume ofn ZVI/BC increased by 19.3%.In addition,elementcompositionand oxygen-containing functional groups of biocharsnZVI/BC and BC changed little.(2)The Langmuir isotherm model fit the experimental data of nZVI/BC and BC very well,which indicated that monolayer adsorption is the main mechanism.Meanwhile,compared to unmodified biochar,cadmium adsorption capacity of n ZVI/BC increased by 107.96%;(3)The Elovich equation model fit the experimental data of nZVI/BC very well,which show that adsorption was dominantedby non-homogeneous chemical reaction.andthe pseudo-second-order modelfit the experimental data of BC well,show that cadmium removal process was influenced by the chemical adsorption rate;(4)The solution pH value,initial concentration and the feed flow rate werekey factor affecting the efficiency of dynamic adsorption.ThenZVI/BC still has excellent buffering capacity after the saturated adsorption.Nitric acid can be used to e regeneratedsorbents used and recycled precious metal resources.(5)Dynamic sorption experiments showed that the capacity of Cd adsorption innZVI/BC is about twice capacity of BC.